1. Field of the Invention
The present invention relates to a pattern formation method, a pattern, and an etching method, an electronic device manufacturing method, and an electronic device using the same. In more detail, the present invention relates to a pattern formation method which is favorably used for in steps of manufacturing semiconductors such as IC, manufacturing circuit boards such as liquid crystals and thermal heads, steps of manufacturing MEMS and the like, and other photofabrication lithography steps, as well as an etching method, an electronic device manufacturing method, and an electronic device which use this pattern formation method. In particular, the present invention relates to a pattern formation method and a pattern, which are favorable for exposure using a KrF or ArF exposure apparatus and an ArF liquid immersion type projection exposure apparatus in which far ultraviolet ray light with a wavelength of 300 nm or less is set as the light source, as well as an etching method, an electronic device manufacturing method, and an electronic device which use the pattern formation method and the pattern.
2. Description of the Related Art
Since resists for KrF excimer lasers (248 nm) came into use, a pattern formation method in which chemical amplification is used has been used in order to compensate for decreases in sensitivity due to light absorption. For example, in a positive type chemical amplification method, firstly, a photoacid generator which is included in an exposed section generates an acid due to being decomposed by light irradiation. Then, in a baking (Post Exposure Bake: PEB) process after exposure or the like, an alkali-insoluble group which is included in a photosensitive composition is changed to an alkali-soluble group by a catalytic action of the generated acid. After that, development is performed using, for example, an alkali solution. By doing this, the exposed section is removed to obtain a desired pattern (for example, refer to JP3632410B and the like).
In the method described above, various types of developers have been proposed as alkali developers. For example, a water-based alkali developer of a 2.38 mass % tetramethyl ammonium hydroxide aqueous solution (TMAH) is widely used as the alkali developer.
In order to refine semiconductor elements, the wavelength of the exposure light sources is being shortened and the numerical aperture (high NA) of the projection lens is being increased and, currently, an exposure apparatus in which an ArF excimer laser which has a wavelength of 193 nm is the light source is being developed. As a technique for further increasing the resolving power, a method (that is, a liquid immersion method) has been proposed in which a liquid with a high refractive index (also referred to below as an “immersion liquid”) is filled between a projection lens and a sample. In addition, EUV lithography in which exposure is performed with ultraviolet light with an even shorter wavelength (13.5 nm) has also been proposed.
In recent years, a pattern formation method has also been developed in which a developer which includes an organic solvent is used (for example, refer to JP2008-281975A and JP2013-33227A).